tune that rigging
John de Frayssinet (editor of
Get your sailcraft moving really well! You can achieve
an extra ‘sparkle without knowing all the finer details of tuning standing
rigging. What’s more, unless you own at least two oil wells, it is
unlikely that you will be able to call upon the services of sail-trim
experts and spar makers.
Some cruising men consider any effort to get the best
out of their boat as rather unnecessary, and this is borne out by the fact
that, come fitting out time, the mast is just sort of stuck up, and that
is the end of it. In fact, a small amount of time and effort to ensure
that your mast is correctly stepped can completely transform the sailing
performance of your boat.
Performance to windward can be most affected by bad
tune. If the mast is not dead upright athwartships then the yacht will not
sail equally well on either tack. Ensure that there is sufficient tension
in the forestay to prevent the luff of the jib from sagging away to
leeward. It is most important that the mast does not develop kinks when
hard on the wind. Adjustment of the cap and inner
shrouds will prevent this.
The rake of the mast is also
important. If the mast is raked too far aft the centre of effort will also
be brought aft, causing excessive weather helm. The mast rake should be
set to ensure a small degree of weather helm when sailing under full
canvas in about 15 knots of wind. A yacht tuned with a degree of lee helm
is potentially dangerous, as the boat may bear away from the wind, causing
an accidental gybe.
Three-quarter rigged boats are getting more common
again. The main advantages in such a rig appear to be that a greater
degree of adjustment can be given to setting the mainsail. In the modern
yacht design which depends largely upon the drive of a large foresail. I
question whether this additional adjustment of the main will compensate
for the loss in foresail area.
be stepped dead centre of boat. Adjust rigging with bare poles
to ensure the mast is upright. Sail in about 1S knots wind
hard to windward. Adjust weather main shroud to eliminate mast
sagging to leeward. Adjust lower shrouds to take out mast sag.
I Fore inner shrouds should have higher tension than aft
inners. Main shrouds taut. Tack and repeat for other side.
Forestay should be
tightened to straighten mast when hard on - wind and foresail
well sheeted. Forestay must not sag away with jib when hard on
Boat should show slight weather helm. This means the boat has
tendency to point higher towards the wind.
If weather helm too
great, - tune stays to bring forward the mast.
If lee helm (boat tends to bear away
from wind) adjust stays to bring mast aft.
adjustments bring mast fore and aft. Adjustment of backstay
only will increase tension.
inner shrouds can bend centre of mast fore or aft. Mast should
become straight when hard on the wind.
of mast only is supported by forestay. This will allow bending
of upper mast. Rake of mast held by running stays. Only
weather runner must be under tension as boom fouls lee runner.
Adjust main, and inner shrouds, fore and running stays as for
masthead rig. Mark runner tensioners when correct tune found
to ensure tune maintained after tacking.
support top of mast. Mast can be bent forward by increasing
shroud tension. Bend occurs above forestay. This will increase
tension on mainsail leech.
If upper shrouds are not self balancing,
ensure tensions bring mast straight.
To bring centre
of effort forward (e.g. for off wind) let off runners, ease
tension on backstay and tension forestay.
in (7) Upper
mast bent forward by upper shroud tension.
in (8) Upper mast bent aft,
easing mainsail leech. Maintain tension on forestay and
runners. Tension backatay and loosen upper shrouds if
names of components
1. Main shroud
2. Back stay
4. inner forestay
5. Fore inner shroud
6. Aft inner shroud
7. Backstay tensioner.
10. Running stay.